Variables being investigated	Study	Measurement of medication adherence	Study setting and sample size
Knowledge about hypertension management	Hussain et al. [34]	Questionnaire	Bangladesh; N = 120
	Nsitou et al. [41]	Questionnaire	Congo; N = 212
	Gelaw et al. [35]	Questionnaire	Ethiopia; N = 91
Belief about medication	Boima et al. [26]	MMAS 8	Ghana and Nigeria; N = 357
	Saleem et al. [39]	Qualitative	Pakistan
	Shima et al. [51]	Qualitative	Malaysia
	Al-Ramahi et al. [38]	MMAS 8	Palestine; N = 450
Avoiding side effect of medications	Campbell et al. [42]	MMAS 4	Nigeria; N = 262
	Hareri et al. [36]	Questionnaire	Ethiopia; N = 365
	Praveen et al. [30]	Questionnaire	India; N = 804
Do not understand drug regimen well	Gelaw et al. [35]	Qualitative	Ethiopia
Do not understand drug regimen well	Odusola et al. [40]	Qualitative	Nigeria